1. Field of the Invention
The present invention relates to an ink jet recording apparatus which discharges color ink to effect color recording.
2. Related Background Art
In the art of a color recording apparatus, thermal transfer, electro-photographic and ink jet recording methods have been used. Among others, the ink jet recording method has recently been attracting notice because it can offer a highly fine image with a low cost.
In a color ink jet recording apparatus, a plurality of heads for jetting (discharging) inks of three primary colors are arranged and they are repeatedly scanned over a record sheet to effect recording. In U.S. Pat. No. 4,320,406, U.S. Pat. No. 4,855,752 and EP 481,829 (U.S. application Ser. No. 600,640 now abandoned) disclose a method for jetting inks of a plurality of colors from a single head.
However, the prior art apparatus has the following disadvantages. Where a plurality of discharge ports, for example, discharge nozzles are formed in one head, the volumes of droplet discharged from the nozzle at an end and the nozzle at a center are different because of a difference in the diameters of the nozzles due to the difference in the flow of etchant in forming the nozzle by etching, or a difference of propagation of pressure to discharge the droplets. Such difference in the volumes of the droplets appears as ununiform density on a record sheet and lowers the image quality.
In the prior art apparatus, when recording is to be effected by using three primary colors (yellow, magenta and cyan), the ends of the respective colors overlap so that the ununiformity of colors is amplified and they appear in stripe.